Embryonic stem cells expansion

Chen S, Oh SKW. (2010) Human embryonic stem cell expansion and differentiation for clinical applications. Available online on www.aiche.org/SBE/Publications/Articles.aspx http //www.lw20.eom/201205191054769.html cf Cortes-Caminero M. (2010) The engineering of stem cells. SBE supplement Stem cell Eng. Chem. Eng. Prog., Nov. 34. 

Fernandes, A. M., Fernandes, T. G., Diogo, M. M. et al. 2007. Mouse embryonic stem cell expansion in a microcarrier-based stirred culture system. J Biotechnol 132(2) 227-36. 

Fok, E. Y. L. and Zandstra, P. W. 2005. Shear-controlled single-step mouse embryonic stem cell expansion and embryoid body-based differentiation. Stem Cells 23(9) 1333-42. 

Fernandes-Platzgummer AM, Baptista RP, Diogo MM, da Silva CL, Cabral JM. 2011. Scale-up of mouse embryonic stem cell expansion in stirred bioreactors. Biotechnol Prog DOl 10.1002/btpr.658. 

Knowledge gained from cell adhesion studies with SAMs has been used to develop culture substrates with the appropriate cell adhesion glycoproteins for different types of cells [7-10], Stem cells, capable of self-renewal and differentiation into multiple cell types, are found in embryonic and adult tissues. Pluripotent stem cells, like embryonic stem cells and induced pluripotent stem cells, have been developed in vitro. These cells are expected to provide cell sources for regenerative medicine. Various culture conditions have been developed to enable expansion of these cells without loss of their multi- and pluripotency and to induce differentiation into viable cells with specific functions. 

Embryonic stem cells (ESCs) are cells isolated from the inner mass of blastocysts." The mechanisms by which ESCs maintain self-renewal and pluripotency are still not yet fully understood. Many reports highlight the involvement of miRNAs as crucial players in ESCs regulation and ESCs development. In fact ESCs lose their self-renewal differentiation capacity, following alterations in the machineiy involved in miRNAs processing, maintenance and activity. Potential clinical applications of ES cells raise many practical and ethical concerns. Many nations currently have moratoria on either ES cell research or the production of new ES cell lines. Because of their combined abilities of unlimited expansion and pluripotency, embiyonic stem cells remain a theoretically potential source for regenerative medicine and tissue replacement after injuiy or disease. 

In fact the transition from bench to market of combination products is often hindered by a series of scientific and economic issues. Both the determination of the ideal cell type and the ideal biomaterial for the specific application can be problematic. Often, the use of autologous differentiated cells would be the best solution, but their use may not be feasible because of limitation on isolation and expansion. Moreover, the use of autologous cells also can introduce infections risks deriving from the use of xenogenic factors or animal feeder layers in culture. Hopefully, adult and embryonic stem cells may provide alternative solutions. Also the determination of the most suitable biomaterial for the specific application is a challenge. Most of the currently available synthetic materials are subjected to a foreign body reaction that can lead to serious complications when implanted in the human body. The use of natural scaffolds circumvents this problem, but it introduces other drawbacks such as inappropriate mechanical properties. Smart combinations of synthetic scaffolds modified with natural... 

Cormier, J. T., Zur Nieden, N. I., Rancourt, D. E., and KaUos, M. S. 2006. Expansion of undifferentiated murine embryonic stem cells as aggregates in suspension culture bioreactors. Tissue Eng 12(11) 3233-45. 

Krawetz, R., Taiani, J., Liu, S. et aL 2010. Large-scale expansion of pluripotent human embryonic stem cells in stirred suspension bioreactors. Tissue Eng Part C, Methods 16(4) 573-82. 

Liu, H., Collins, S. R, and Suggs, L. J. 2006. Three-dimensional culture for expansion and differentiation of mouse embryonic stem cells. Biomaterials 27(36) 6004-14. 

Lock, L. T. and Tzanakakis, E. S. 2009. Expansion and differentiation of human embryonic stem cells to endoderm progeny in a microcarrier stirred-suspension culture. Tissue Eng A 15(8) 2051-63. 

M.R. Zonca, Jr., P.S. Yune, C.L. Heldt, G. Belfort, and Y. Xie, High-throughput screening of substrate chemistry for embryonic stem cell attachment, expansion, and maintaining pluripotency, MacromoZ. Biosci., 13 (2) 177-190, Feb. 2013. 

D. Hernandez, L. Ruban, and C. Mason, Feeder-free culture of human embryonic stem cells for scalable expansion in a reproducible manner. Stem Cells Develop., 20 (6) 1089-1098, Jun. 2011. 

M.R Storm, C.B. Orchard, H.K. Bone, J.B. Chaudhuri,and M.J. Welham,Three-dimensional culture systems for the expansion of pluripotent embryonic stem cells, Biotechnol Bioeng., 107 (4) 683-695, Nov. 2010. 

M. Serra, C. Brito, M.R Sousa, J. Jensen, R. Tostoes, J. Clemente, R. Strehl, J. Hyllner, M.J. Carrondo, and PM. Alves, Improving expansion of pluripotent human embryonic stem cells in perfused bioreactors through oxygen control, J. Biotechnol, 148 (4) 208-215, Aug. 2010. 

Randle, W.L. et al (2007) Integrated 3D expansion and osteogenic differentiation of murine embryonic stem cells. 

Efficient stem cell expansion is a key bottleneck for clinical application and commercialization of stem cell therapy. Membrane bioreactors may make a significant contribution due to its important features such as possibility for uniform chemical and biochemical conditions within the bioreactor, low or even zero hydrodynamic shears, large surface-to-volume ratios, and physical separation between two cell types but allowing biochemical signaling between them. For example, it may be possible to culture the feeder cells on one side of the membrane, while culturing human embryonic stem cells on the other. In this way human embryonic stem cells are not mixed with the feeder cells, which eliminates the need for later difficult separation, but get the biochemical signals from the feeder cells that are necessary to proliferate embryonic stem cells (e.g., Choo et al., 2006 Klimanskaya et al., 2005). 

Abranches, E., E. Bekman, D. Henrique et al. 2007. Expansion of mouse embryonic stem cells on microcarriers. Biotedmol Bioeng96 6) 1211-21. 

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